One of the great joys of life for this earth scientist is to watch the demise of a paradigm, long-etched in stone, before the relentless onslaught of new technology and new data in the hands of bright minds. With no malice toward any paradigm, the joy is for the beautiful journey to the inimitable truths. In this issue of Geotimes, we highlight some of the contributions the earth sciences are making to the field of archaeology, including both scrutiny of conventional wisdom and foundations for new paradigms.

According to Lionel Jackson and Michael Wilson in the opening feature article, "The Ice-Free Corridor Revisited," new science seems to be moving this favored alternative, for the southward migration route that peopled North America roughly 11,000 years ago, toward the permanent deep freeze. Regional mapping and dating of glacial sediments has been underway along the eastern flank of the Canadian Cordillera, where the corridor was postulated to have existed between the eastward-flowing mountain glaciers and the southwestward-moving continental ice sheet. The results of this geological work, together with recent studies of archeological sites, mammal bones and botanical samples in the critical area, lead the authors to a confronting conclusion {emdash} there was no ice-free passage south along the eastern margin of the Cordillera in the time period in question, leaving geoarchaeologists to pursue a different migration route for early people.

Our second feature picks up where the first left off. Renée Hetherington and colleagues ("Quest for the Lost Land") discuss nearly a half-century of research exploring the possibility of a migration route down the coast of British Columbia. Drowned forests and beaches, discovery of a 41,000-year-old black bear on Prince of Wales Island and a 12,000-year-old mountain goat in caves on northern Victoria Island invite speculation that greater expanses of habitable, ice-free land existed than can be documented given present high sea levels. The authors point out that the coast is coincident with both a plate boundary and the western edge of ice loading, each favorable for isostatic movement that could form and preserve now-flooded transportation routes. The growing acceptance of this idea seems precisely timed with the first sign of weakness in the reigning "ice-free corridor" interpretation. What would it have taken for the nascent paradigm to take off even before the reigning hypothesis became wanting?

The balance of our features are vignettes, written by the Geotimes staff, selected from an array of incursions of earth science into archaeology. Also on the hunt for early Americans, geologists in Kansas are working to push back the age of mid-continent Paleo-Indians beyond that currently assigned to ancient Americans, and they are doing it in a thoughtful way {emdash} looking at buried soil horizons. This geologically focused approach is working and he has identified several new, buried sites of human activity.

In another effort, aimed at linking volcanic ash plumes to civilization changes, geologists and archaeologists are at an impasse in an "Aegean volcanic dating dilemma." Geological dating of the plumes, based on volcanic glass and acid snow in Greenland ice core, put the eruption of Thera in the Greek Mediterranean at 1645 B.C., while archaeological artifacts place the date around 1550 B.C. or later. As intellectually satisfying as it might be to resolve the 1450 B.C. demise of the Minoan civilization with a volcanic eruption, this dating debate is standing in the way. Has another paradigm reached the "tipping point"?

From ancient Greece, we travel to modern-day Manhattan, where geologists are digging their way to understanding the most urban setting in the world, again looking at layers in the horizon. And, then our vignettes head back to the Old World. In a challenge of biblical proportions, some Eastern European scientists are questioning past interpretations of the flooding history of the Black Sea and its (mis-?) linkages to Noah's flood. Not too far away, in Egypt's delta, a geologist is using satellite imagery to help locate new archaeological sites from Egypt's Old Kingdom. Finally, we explore how the mineralogical and chemical clues the Austrian Iceman carried in his 5,200-year-old remains suggest what mountain valleys he frequented.

So what might one draw from our accounts of geoarchaeology? Down the tapestry of history from more than 11,500 years ago for the arrival of Paleo-Indians in the midcontinent, through 9,000-year-old salt-loving mollusks perhaps marking incursion of ocean water into the Black Sea region, to the 5,200-year-old clay residue in the intestines of the Iceman and the still-uncertain relations between volcanism and the end of the Bronze Age circa 3,500 years ago, earth scientists and their tools and skills are playing an indispensable role in understanding our place in time and on Earth. Can there be a more exciting and significant role for the earth sciences than building a temporal and spatial context for the species that changed to world?